Fast response and selective perchlorate polymeric membrane electrode based on bis(dibenzoylmethanato) nickel(Ⅱ) complex as a neutral carrier

摘要

The feasibility of a synthesized bis(dibenzoylmethanato) Ni(Ⅱ) complex (Ni(DBM)_2), as a novel ionophore for the preparation of a solid ion selective polymeric membrane (PVC) was tested. The ionophore has shown with the enhanced potentiometric selectivity toward perchlorate compared to otheranions. The selectivity sequence of this electrode is asfollows: ClO_4~- > SCN~- > I~- > CN~- > ClO_3~- > NO_3~- > Br~- > SO_3~- > BrO_3~- > F~- > Cl~-, which is a Hofmeister selectivity sequence. The proposed electrode possesses a very wide Nernestian potential linear range to perchlorate from 1.0 x 10~(-6) to 1.0 x 10~(-1) M (0.138 μg mL~(-1) to 138 mg mL~(-1)), a low detection limit (6.6 x 10~(-7) M) and good perchlorate selectivity over the wide variety of other anions. The developed electrode has an especially fast response ( < 5 S) and a wide pH independent range (1.2-12.5) in comparison with recent reported electrodes. The proposed electrode was used for the determination of perchlorate in water samples and human urine with satisfactory results.